Frequency Regulation Participation of Highly Penetrated Wind Power Considering Dynamics of Synchronous Power Plant

Wind power can participate in frequency regulation of the power system using stepwise inertial control after a disturbance. Existing research works on stepwise inertial control only consider the frequency dynamics of the power system based on conventional system frequency response model. However, the dynamics of the boilers connected with the synchronous generators are ignored. Consequently, after some large disturbances, the throttle pressure will fluctuate or even exceed the lower limit due to the over-release of the thermal energy stored in the boiler. In this case, valve opening will be reduced, and thus the active power output of the generator will be decreased, resulting in further decline of the system frequency. In view of this, this paper proposes a new system frequency response model with dynamics of wind power and boiler, then the relationship between the throttle pressure, frequency, disturbance, power increment of wind turbines (WTs) and termination time is analyzed. Furthermore, in order to maintain the throttle pressure of the boiler and the frequency deviation of the power system both within their safety range, the range of WT’s incremental power and termination time is obtained through simulations. The proposed method is verified by case studies.